Slater blasted a solo home run to center field off Brewers starter Paolo Espino in the Giants' 9-5 extra-innings win on Thursday. The dinger traveled a Statcast-projected 461 feet, with a 111-mph exit velocity, making it the longest by any Giants hitter and longest by any rookie in baseball this season.

"Honestly, I felt like I was getting more comfortable my first start here in Milwaukee," Slater said. "The first two in Philly, everything was moving quick, because that's something you look forward to your whole life playing ball. I put together some good at-bats the last couple of at-bats Tuesday. I felt great at the plate today."

A's infielder Chad Pinder had the previous longest for a rookie at 460 feet. Judge, who has electrified baseball this season with 18 mostly towering home runs, hit his longest 457 feet.

With a 3-2 count, Slater capitalized on Espino's high ball up in the zone and sent it to the Miller Park scoreboard in 4.8 seconds, according to Statcast™. The ball bounced off the scoreboard and into the park, so Slater was able to keep his souvenir after the game.

"What are the odds of that? Only here in Milwaukee. I'm thankful it happened. It is definitely something I will keep forever," Slater said.

It was the second-longest home run by a Giant in the Statcast™ era behind only Brandon Belt's 475-foot homer on May 22, 2015, and is currently tied for the 18th longest in the Majors this year.

"He was swinging the bat well down there," Bochy said. "You get a little grace period there. They're trying to get settled in. He got a good swing out there. He hit it well, too. It got some pop. He's more of a line drive gap guy but he gets it in the air. I've seen some long ones by him, so it was good for him to get that run."

Slater is the Giants' No. 17 prospect per MLBpipeline.com. His contract was purchased prior to Friday's game against the Phillies and he made his MLB debut that night. Slater entered Thursday's game batting .167 (2-for-12), with a run and a walk. He was hitting .322 (56-for-174) with four home runs in 46 games with Triple-A Sacramento.

Carson Mason is a reporter for MLB.com based in Milwaukee and covered the Giants on Thursday.